Ok, my reasons for the trade are such:
For Boston: Obvious, we'd be legit with 2 superstars in their prime, a HOF Big 3 in their twilight, and 2 role players in their prime (Ariza, Delonte), and we'dd still have our MLE.
For New Orleans: They're losing Paul anyways, so get they get Rondo & Green and dump the contracts of Okafor, West, and Ariza.
For Orlando: They need something like this. They are in a cap nightmare for the next 3-4 years. They are also in decline as a team. Okafor and West combined with numerous picks will keep them afloat until they are out of cap prison. In time they may be able to move some of their contracts, but nobody is taking any of them right now. Howard can leave for nothing if Orlando isn't careful.
This trade would need to be done after this years draft, before the season starts. Allen and JO could also be bought out, potentially saving New Orleans more money, and would be almost nessecary for Boston.
Note: Completely depnadant on structure of new CBA